Latch lock

ABSTRACT

A latch lock which makes possible, when opening a door, to release the latch by a simple operation without the necessity of turning a knob or the like. The lock has a latch head with a grooved boss fitting into a case. The latch head is urged outwardly of the case by a spring, and has a shape which enables it to be turned and also advanced and withdrawn freely. A stop is provided which is engageable with the grooved boss to prevent the latch head from turning when the stop is engaged.

United States Patent 1 Taniyama Mar. 26, 1974 LATCH LOCK [75] Inventor:Mitsumasa Taniyama, Osaka, Japan [73] Assignee: Goal Lock Company,Osaka, Japan [22] Filed: May 9, 1972 21 Appl. No.: 251,759

[52] US. Cl. 292/71, 292/64 [51] Int. Cl. E05c 5/02 [58] Field of Search292/63, 64, 65, 66, 67, 292/71, 201

[56] References Cited UNITED STATES PATENTS 202,474 4/1878 Ruggles292/63 1,199,199 9/1916 Mason 292/201 2,482,959 9/1949 Anderson et a].292/63 Primary Examiner-Richard E. Moore Attorney, Agent, orFirm-Wenderoth, Lind & Ponack [5 7] ABSTRACT A latch lock which makespossible, when opening a door, to release the latch by a simpleoperation without the necessity of turning a knob or the like. The lockhas a latch head with a grooved boss fitting into a case. The latch headis urged outwardly of the case by a spring, and has a shape whichenables it to be turned and also advanced and withdrawn freely. A stopis provided which is engageable with the grooved boss to prevent thelatch head from turning when the stop is engaged.

1 Claim, 8 Drawing Figures LATCH LOCK The present invention relates to alatch lock which locks a door securely, and more particularly relates toa latch lock with which it is possible, when opening the door, toreadily unlock the latch by a simple operation without the necessity ofproviding a mechanism, as required with the conventional latch locks,for with drawing the latch head by turning a knob, and which provides ameans to securely lock the door when closing it.

An object of the present invention is to provide an improved latch lockhaving an altogether new mechanism which is not to be found with latchlocks hitherto in existence, whereof the manufacturing cost is low, andwhich is simple to operate.

Another object of this invention is to provide a latch lock with which,when closing the door, it is possible, unlike with the conventionallatch locks, to lock the door completely like with a genuine lock,whereas, when opening the door, a stop plunger, which serves to stop thelatch head by engaging it, is lifted out of engagement thus making itpossible to open the door without turning a knob but rather by rotatingthe latch head against the resilient force of a spring.

A further object of the invention is to provide a latch lock which, inan emergency, by means of a solenoid mechanism connected to detectingdevices such as a fire alarm, a smoke detector or the like lifts theaforementioned stop plunger, and unlocking is effected by merelyrotating the latch head as the door is opened.

A still further object of the present invention is to provide a latchlock having few parts and having a simple structure, and which istherefore inexpensive and well suited for mass production.

These objects are attained by an improvement in the combination of theconstituent parts of the present invention and by their operation and anembodiment of the invention is provided in the accompanying drawings anda detailed description which follows.

According to the present invention, a latch head is fitted into a lockcase, with an interposed spring, so as to be capable of advancing andwithdrawing freely. The latch head is provided, on boththe upper andlower sides, with a groove the bottom of which slopes from the fore downtoward the rear; and a stop plunger for preventing the latch head fromrotating, is fitted, with an interposed spring, into the said groove ina manner such that the stop plunger can move up and down as the occasiondemands and such that its end touches the bottom slope of the groove.

By virtue of the aforementioned mechanism, the door, when closed, cannotbe opened since the stop plunger fits into the groove of the latch headand prevents it from rotating; lifting the stop plunger enables thelatch head to rotate and withdraw so that the door can be opened.

In the accompanying drawings:

FIG. 1 shows an oblique view of the latch head to be used for the latchlock in question;

FIG. 2 is a front elevation of the said latch head;

FIG. 3 is a rear view of the same;

FIG. 4 is a plan of the same;

FIG. 5 is a sectional view of the latch head, across the 5 5 line shownin FIG. 2.

FIG. 6 is a cross section of a lock case fitted with the latch lock inquestion, sectioned across the line 6 6 as shown in FIG. 7;

FIG. 7 is a longitudinal section of the said lock case, across the line7 7' as shown in FIG. 6; and

FIG. 8 is a cross-sectional view of the same, across the 8 8' line shownin FIG. 7.

The invention will now be explained in further detail with reference tothe drawings:

The latch head 10 is approximately rhombiform in plan and consists oftwo parts, although it is of a unitary construction, i.e., the tongue,which has an oblique and curved side 11, and the boss 12. The upper andlower sides of the boss are each provided, at their respective centers,with a groove 13 whereof the bottom slopes from the rear end up towardthe fore, and further a cut is made into the rear of the boss, at itscenter, so that there will be formed a curved bearing surface 14 againstwhich a spring shoe is to hear.

The latch head 10 is fitted, with an interposed spring 17 into a lockcase 16, the distance between the side plates 15 and 15' of the case 16'being approximately equal to the width of the said latch head, so thatthe latch head is able to advance and withdraw freely; and a stopper,shown as a stop plunger 18 is fitted, with an interposed spring 19, tothe said side plates of the lock case so as to be capable of moving upand down and so that one end touches the sloping bottom of the groove 13as mentioned above.

The numeral 20 indicates the side of the latch head which engages thecatch and fastens the door; and the numeral 21 denotes the front plateof the lock case 16, through which an outlet 21a is bored for the tongueof the latch head, the outlet being approximately the same shape as, andserving as the primary guide for, the tongue.

The numerals 22 and 23 represent the guide plates, fixed to the sideplates 15 and 15' of the lock case, for the latch head; the numeral 24denotes a spring shoe fastened to the back plate 25 of the lock case;and 26 represents another spring shoe having bends 26a and 26b as guidesand touching the curved bearing surface 14 of the latch head, impelledby the resilient spring 17.

The numeral 27 indicates a plate, fixed to the side plates of the lockcase, having a hole through which the stopplunger 18 is inserted. Thenumeral 28 represents a stopper, attached to the rear end of the saidstop plunger, which prevents the stop plunger from falling and to whichis connected a solenoid mechanism 30 by means of solenoid shaft 31 forlifting it. Numeral 29 represents a spring shoe which is fastened to thestop lever.

Now turning to the operation of said latch lock, FIG. 6 shows it in alocked condition, that is to say, the tongue of the latch head 10 issticking out of the lock case, impelled by the resilient force of thespring 17, while the boss 12 limits its maximum extension.

When a door fitted with the subject latch lock closes, the curved,oblique side 11 of the tongue of the latch head hits against the curvedpart of a strike (not shown) provided in the door case, and since thishitting force is converted, by virtue of the said oblique side, into aforce which works in the orthogonal direction, the latch head starts towithdraw, over coming the resilient force of the spring 17.

As the latch head withdraws, the sloping bottom of the groove 13provided on the upper side of the boss 12 at its center, pushes the stopplunger 18 up, overcoming the resilient force of the spring 19 andtherefore the latch smoothly withdraws, without any hitch whatever,until an unlocked condition is reached. Once the latch head passes overthe said curved part of the strike and falls into the catch-hole of thestrike (not shown), it again extends by virtue of the resilient force ofthe spring, thus locking the door. (At this point of time, the stopplunger 18 will also have regained its original position, impelled bythe resilient force of the spring 19.)

As long as the latch lock remains in an extended condition, the doorwill not open even if a force is applied in an attempt to open it sincewhile the latch head will attempt to rotate on the fulctrum of thecorner a of the boss 12, the stop plunger 18 with the side b of thegroove 13 on the upper side of the boss and prevents the latch head fromturning, thus keeping the door locked.

When, however, the stopper 28 of the stop plunger 18 is connected with alifting mechanism operated by means of a sliding thumbturn, solenoid, orthe like, the stop plunger 18 is, as it is lifted, disengaged from theside b of the groove; and so, as a force is applied in the direction ofopening the door, the latch head rotates on the fulcrum of the corner aof the boss, as is illustrated in FIG. 8.

As additional force is exerted in an attempt to open the door, theengaging side 20 of the latch head works likewise as the curved bearingsurface 14 and the latch head retracts into the lock case and thus thedoor is unlocked.

Thereafter, the aforementioned operation is repeated every time the dooris opened and closed.

As will be seen from the foregoing description, the latch lock accordingto the present invention requires no latch-retracting mechanism whichoperates in connection with a knob since, when being locked, the latchhead withdraws through the medium ofa spring. Therefore it isinexpensive to manufacture.

Furthermore, since the latch lock can be unlocked by simply lifting thestop plunger, it may be employed to great advantage, by connecting itwith a solenoid mechanism, as an emergency lock that is to say, onewhich can be readily unlocked in an emergency, the stop plungerdisengaging in response to the operation of detecting devices such as afire alarm, smoke detector, or the like.

As such, the latch head of the present invention has a very wideapplication.

It is to be clearly understood that the scope of the claim of thepresent invention is by no means restricted to the aforementionedembodiment thereof but that some variations and modifications come underthe scope of claim of the present invention.

What is claimed is:

l. A latch lock for a door, comprising:

a lock case defining an aperture at one end thereof;

a latch head having a boss defining an engaging groove thereinoperatively positioned within said lock case and a tongue extendingoutwardly through said aperture, said boss having an end rear portionand a centrally located front portion;

a spring interposed within said lock case between said latch head andthe end of said lock case opposite the end of said case defining theaperture, said latch head and spring being arranged such that said latchfreely advances and withdraws relative to said lock case and rotatesabout a corner of said boss;

a stop operatively positioned for engaging in and disengaging from saidlatch head engaging groove, said groove downwardly sloping from thefront portion of the boss toward the back portion of the boss such thatsaid latch head withdraws and then advances without rotation whenclosing said door when said stop is in engagement with said latch lockgroove and said latch lock being restrained from rotation when engagingsaid stop, thus preventing a locked door from opening when said stop andsaid latch head are in engagement.

1. A latch lock for a door, comprising: a lock case defining an apertureat one end thereof; a latch head having a boss defining an engaginggroove therein operatively positioned within said lock case and a tongueextending outwardly through said aperture, said boss having an end rearportion and a centrally located front portion; a spring interposedwithin said lock case between said latch head and the end of said lockcase opposite the end of said case defining the aperture, said latchhead and spring being arranged such that said latch freely advances andwithdraws relative to said lock case and rotates about a corner of saidboss; a stop operatively positioned for engaging in and disengaging fromsaid latch head engaging groove, said groove downwardly sloping from thefront portion of the boss toward the back portion of the boss such thatsaid latch head withdraws and then advances without rotation whenclosing said door when said stop is in engagement with said latch lockgroove and said latch lock being restrained from rotation when engagingsaid stop, thus preventing a locked door from opening when said stop andsaid latch head are in engagement.